it's meant to be 'Two nuns are in a bath, one says wear's the soap? the other says 'it does rather doesn't it.'
basically the first nun wants to know where the soap is, but the second one thinks she is saying that because the second nun is using the soap, it is being worn out, hence 'wears'
^ i just looked it up because i didn't get it, i kind of get it now. : )